Processing of facial affect in social drinkers: a dose-response study of alcohol using dynamic emotion expressions

Limited evidence that alcohol affects emotional face processing via interoceptive pathways, a registered report

BACKGROUND

Our brain uses interoceptive signals from the body to shape how we perceive emotions in others; however, whether interoceptive signals can be manipulated to alter emotional perceptions is unknown. This registered report examined whether alcohol administration triggers physiological changes that alter interoceptive signals and manipulate emotional face processing.

METHODS

Participants (n=36) were administered an alcohol or placebo beverage. Cardiovascular physiology (Heartrate variability, HRD) was recorded before and after administration. Participants completed a behavioral task in which emotional faces were presented in synchrony with different phases of the cardiac cycle (i.e., systole/diastole) to index of how interoceptive signals amplify them.

HYPOTHESES

We hypothesized that alcohol administration would disrupt the cardiac amplification of emotional face processing. We further explored whether this disruption depended on the nature and magnitude of changes in cardiovascular physiology after alcohol administration.

RESULTS

We observed no main effects or interactions between alcohol administration and emotional face processing. We found that HRV at baseline negatively correlated with the cardiac amplification of emotional faces. The extent to which alcohol impacted HRV negatively correlated with the cardiac amplification of angry faces.

CONCLUSIONS

This registered report failed to validate the primary hypotheses but offers some evidence that the effects of alcohol on emotional face processing, if any, could be mediated via changes in basic physiological signals that are integrated via interoceptive mechanisms. Results are interpreted within the context of interoceptive inference and could feed novel perspectives for the interplay between physiological sensitivity and interoception in the development of drug-related behaviors.

Sex differences in ethanol consumption and drinking despite negative consequences following adolescent social isolation stress in male and female rats

Alcohol use disorder (AUD) is a debilitating psychiatric disorder characterized by drinking despite negative social and biological consequences. AUDs make up 71% of substance use disorders, with relapse rates as high as 80%. Current treatments stem from data conducted largely in males and fail to target the psychological distress motivating drinking in stress-vulnerable and at-risk populations. Here we employed a rat model and hypothesized that early life stress would reveal sex differences in ethanol intake and drinking despite negative consequences in adulthood. Rats were group housed or isolated postweaning to evaluate sex and stress effects on ethanol consumption in homecage drinking, self-administration (SA), and punished SA (drinking despite negative consequences) in adulthood. Stressed rats showed elevated homecage ethanol intake, an effect more pronounced in females. During SA, males were more sensitive to stress-induced elevations of drinking over time, but females drank more overall. Stressed rats, regardless of sex, responded more for ethanol than their non-stressed counterparts. Stressed females showed greater resistance to punishment-suppressed SA than stressed males, indicating a more stress-resistant drinking phenotype. Results support our hypothesis that adolescent social isolation stress enhances adult ethanol intake in a sex- and model-dependent manner with females being especially sensitive to early life stress-induced elevations in ethanol intake and punished SA in adulthood. Our findings echo the clinical literature which indicates that stress-vulnerable populations are more likely to 'self-medicate' with substances. Elucidating a potential mechanism that underlies why vulnerable populations 'self-medicate' with alcohol can lead towards developing catered pharmacotherapeutics that could reduce punishment-resistant drinking and relapse.

The acute effects of alcohol on social cognition: A systematic review of experimental studies

RATIONALE

Alcohol effects on social cognition have been studied by measuring facial emotion recognition, empathy, Theory of Mind (ToM) and other forms of information processing.

OBJECTIVES

Using the PRISMA guidelines, we reviewed experimental studies that examined acute effects of alcohol on social cognition.

METHODS

Scopus, PsycInfo, PubMed, and Embase were searched between July 2020 - January 2023. The PICO strategy was used for identifying participants, interventions, comparators, and outcomes. Participants (N = 2330) were adult social alcohol users. Interventions consisted of acute alcohol administration. Comparators included placebo or the lowest alcohol dose. Outcome variables were grouped into three themes: facial processing, empathy and ToM, and perceptions of inappropriate sexual behavior.

RESULTS

A total of 32 studies were reviewed. Studies measuring facial processing (67%) often found no effects of alcohol on the recognition of specific emotions, facilitated emotion recognition at lower doses and worsened emotion recognition at higher doses. In studies measuring empathy or ToM (24%), lower doses were more likely to lead to improvements while higher doses were generally impairing. Within the third group of studies (9%), moderate to high alcohol doses made it more difficult to perceive sexual aggression accurately.

CONCLUSIONS

Lower alcohol doses might sometimes help facilitate social cognition, but most data were in line with the idea that alcohol tends to worsen social cognition, particularly at higher doses. Future studies might focus on examining other moderators of the effects of alcohol on social cognition, particularly interpersonal characteristics such as trait emotional empathy, and participant and target gender.

The dosing procedure that "makes the poison": Comparing the effects of single versus cumulative alcohol administration methods on emotion recognition

BACKGROUND

Most people often consume alcohol cumulatively and gradually. Yet almost scientific knowledge about alcohol's acute effects on cognition, behavior, and affect stems from laboratory studies that employ a single beverage administration procedure.

OBJECTIVE

This study tests the hypothesis that alcohol's acute effects depend on both methods of administration and alcohol blood level. We introduce a new laboratory procedure for studying cumulative alcohol drinking and examine alcohol's effects on emotion recognition as a function of both alcohol administration method and alcohol blood level.

METHODS

Participants were recruited for one of two studies. One study employed a between-subject design using a single alcoholic dose. Participants were randomly assigned to drink either placebo (0.00%), low (0.03%), moderate (0.06%), or high (0.09%) alcohol levels. The second study employed a within-subject design using a cumulative alcoholic administration method, in which each participant drank four drinks (placebo, followed by three alcoholic drinks). Both groups reached similar breath alcohol concentrations. In both studies, participants attended a single study session, in which emotion recognition was examined following alcohol administration.

RESULTS

Single alcoholic beverage administration method caused greater impairment in emotion recognition ability, specifically for anger, happiness, and fear, as compared with cumulative administration method, even though breath alcohol levels were similar in both conditions.

CONCLUSIONS

This paper presents questions concerning the internal validity of previous laboratory studies that use a single beverage administration procedure. Insights into the effects of alcohol on behavior, as well as regarding our knowledge about models of addiction are presented.

Does alcohol affect emotional face processing via interoceptive pathways?

BACKGROUND

Our brain uses interoceptive signals from the body to shape how we perceive emotions in others; however, whether interoceptive signals can be manipulated to alter emotional perceptions is unknown. Alcohol has acute effects both on emotional processing and on the physiological substrates supporting interoception. In this registered report, we examine whether alcohol administration triggers physiological changes that alter interoceptive signals and manipulate emotional face processing. Such knowledge will broaden understanding of the mechanisms by which alcohol affects emotional face processing.

METHODS

Participants (n = 36) will be administered an alcohol or placebo beverage. Cardiovascular physiology will be recorded before and after administration. Participants will complete two behavioral tasks in which they view emotional faces presented in synchrony with different phases of the cardiac cycle (i.e., systole, diastole). This manipulation creates an index of how interoceptive signals amplify emotional face processing.

HYPOTHESES

We hypothesize that, compared to placebo, alcohol administration will disrupt the cardiac amplification of emotional face processing. We further explore whether this disruption depends on the nature and magnitude of changes in cardiovascular physiology after alcohol administration.

Gender moderates the association between acute alcohol intoxication and facial emotion recognition in a naturalistic field study setting

BACKGROUND

Alcohol intoxication is associated with significant negative social consequences. Social information processing theory provides a framework for understanding how the accurate decoding and interpretation of social cues are critical for effective social responding. Acute intoxication has the potential to disrupt facial emotion recognition. If alcohol impairs the processing and interpretation of emotional cues, then the resultant behavioral responses may be less effective. The current study tested the association between alcohol intoxication and facial emotion recognition in a naturalistic field study of intoxicated participants.

METHODS

114 participants (59.4% men; M_age  = 24.2 years) who had been consuming alcohol were recruited in the downtown area of a mid-size town surrounded by several drinking establishments in the mid-southern United States. Participants were shown images depicting 5 facial displays of emotions (happy, sad, anger, disgust, and no emotion) portrayed by 1 male and 1 female actor per emotion and breath alcohol concentration (BrAC) was measured by the field breathalyzer test (M = 0.078%, SD = 0.052).

RESULTS

BrAC was significantly negatively associated with emotion recognition accuracy when controlling for average alcohol use, B = -.35, t = -2.08, p < 0.05, F(3, 110) = 5.28, p < 0.01, R²  = 0.13. A significant BrAC × gender interaction was revealed, B = -0.39, t = -2.07, p = 0.04, ΔR²  = 0.033, p = 0.04, such that men (but not women) displayed a significant negative association between BrAC and emotion recognition accuracy.

CONCLUSIONS

Acute intoxication was associated with impaired facial emotion recognition, particularly for men, in a field study context. Findings support and extend some previous experimental laboratory-based research and suggest that intoxication can impair the decoding stage of social information processing.

Tackling heterogeneity: Individual variability of emotion decoding deficits in severe alcohol use disorder

BACKGROUND

Severe alcohol use disorder (SAUD) is associated with social cognition deficits. Patients with SAUD are impaired for the recognition of emotional facial expressions, particularly at early stages of abstinence. These deficits damage interpersonal relations and increase relapse risk. However, uncertainties still abound on their variation across emotions and on the heterogeneity of emotional impairments across patients. We addressed these questions by exploring how the deficit varies according to emotions' type/intensity and patients' heterogeneity.

METHODS

Sixty-five recently detoxified patients with SAUD and 65 matched healthy controls performed the Facial Emotion Recognition Test, assessing the ability to identify six emotions (anger, contempt, disgust, fear, happiness, sadness) displayed by morphed faces with various intensities. Accuracy scores and detection thresholds were collected for each emotion. Beyond group comparisons, multiple single-case analyses determined the percentage of patients presenting decoding deficits for each emotion.

RESULTS

When current depression and anxiety symptoms were controlled for, patients did not present a general emotion decoding deficit, but were rather characterized by specific deficits for disgust/contempt in accuracy, and for disgust in detection threshold scores. Single-case analyses showed that only a third of patients presented a clinically significant emotional deficit.

CONCLUSIONS

Patients with SAUD only present emotional decoding deficits for specific interpersonal emotions (disgust/contempt) when subclinical psychopathological states are controlled for, and show no general emotional impairment. This goes against the proposal of a generalized social cognition deficit in this population. This group effect moreover masks a massive heterogeneity across patients, which has implications at experimental and clinical levels.

Effect of alcohol on the sense of agency in healthy humans

Even at low to moderate doses, ingestion of the widely used recreational drug alcohol (ethanol) can impact cognitive and emotional processing. Recent studies show that the sense of agency (SoA; ie, the subjective experience of voluntary control over actions) can be modulated by specific pharmacological manipulations. The SoA, as quantified by the intentional binding (IB) paradigm, is enhanced by direct or indirect dopaminergic agonists in patients with Parkinson's disease and by ketamine (an N-methyl-D-aspartate (NMDA) receptor antagonist) in healthy individuals. These findings implicate dopaminergic and glutamatergic neurotransmission in mechanisms underlying SoA. Alcohol has a complex set of actions, including disinhibition of dopaminergic neurotransmission and allosteric antagonism at NMDA receptors. Here, we tested the hypothesis that low to moderate doses of alcohol would enhance SoA, and impact impulsivity and subjective emotional state. We conducted two experiments in 59 healthy male and female social drinkers, who ingested either a placebo "vehicle," or one of two doses of ethanol: 0.4 and 0.6 g/kg. In both experiments, we observed increased SoA/IB at both doses of alcohol exposure, relative to the placebo condition. We found no correlation between the effects of alcohol on IB and on impulsivity or subjective emotional state. Our findings might have implications for social and legal responsibility related to alcohol use, particularly in states prior to overt intoxication. Further studies are necessary to investigate the effects of alcohol and other addictive substances on the SoA.

Intoxicated aggression: Do alcohol and stimulants cause dose-related aggression? A review

RATIONALE

Violence and drug use are significant public health challenges that are strongly linked. It is known that alcohol plays a major role in the causation of unnatural deaths and that stimulants like cocaine and amphetamine are often implicated in aggressive acts or violence. However, a clear causal relationship between these substances and aggression, and more specifically a blood concentration threshold at which intoxicated aggression emerges is lacking. In case of a crime and subsequent law enforcement, knowledge about dose-response relationships could be of pivotal importance when evaluating the role of alcohol and drugs in aggressive offences.

AIMS

The present review aimed to determine whether there is a causal relation between intoxication with these psychoactive substances and aggression, and to define blood concentration thresholds above which these substances elicit aggression.

METHODS

Empirical articles published between 2013 and 2017 and review papers containing the predefined search strings were identified through searches in the PubMed and Embase databases and additional reference list searches. The complete search query yielded 1578 publications. Initially all articles were manually screened by title and abstract. Articles with irrelevant titles, given the selected search terms and review aims were discarded. Remaining articles were carefully studied and those that did not comply with the main objectives of this review were discarded. At the end of this process, 167 titles were found eligible for review.

FINDINGS AND CONCLUSION

While placebo-controlled experimental studies clearly showed a causal link between alcohol and aggression, it is evident that such a link has not yet been established for cocaine and amphetamines. In case of alcohol, it is clear that there are various individual and contextual factors that may contribute to the occurrence of an aggressive act during intoxication. A clear threshold blood alcohol concentration has not been defined yet for alcohol, but a statistically significant increase of aggression has been demonstrated at a dose of 0.75 g/kg and higher. Future studies into intoxicated aggression should include multiple doses of alcohol and stimulants and take into account individual and contextual factors.

Emerging Technologies Based on Artificial Intelligence to Assess the Quality and Consumer Preference of Beverages

Beverages is a broad and important category within the food industry, which is comprised of a wide range of sub-categories and types of drinks with different levels of complexity for their manufacturing and quality assessment. Traditional methods to evaluate the quality traits of beverages consist of tedious, time-consuming, and costly techniques, which do not allow researchers to procure results in real-time. Therefore, there is a need to test and implement emerging technologies in order to automate and facilitate those analyses within this industry. This paper aimed to present the most recent publications and trends regarding the use of low-cost, reliable, and accurate, remote or non-contact techniques using robotics, machine learning, computer vision, biometrics and the application of artificial intelligence, as well as to identify the research gaps within the beverage industry. It was found that there is a wide opportunity in the development and use of robotics and biometrics for all types of beverages, but especially for hot and non-alcoholic drinks. Furthermore, there is a lack of knowledge and clarity within the industry, and research about the concepts of artificial intelligence and machine learning, as well as that concerning the correct design and interpretation of modeling related to the lack of inclusion of relevant data, additional to presenting over- or under-fitted models.

Effects of acute alcohol consumption on emotion recognition in social alcohol drinkers

BACKGROUND

Research suggests that acute alcohol consumption alters recognition of emotional expressions. Extending this work, we investigated the effects of alcohol on recognition of six primary expressions of emotion.

METHODS

We conducted two studies using a 2 × 6 experimental design with a between-subjects factor of drink (alcohol, placebo) and a within-subjects factor of emotion (anger, disgust, sadness, surprise, happiness, fear). Study one ( n = 110) was followed by a direct replication study ( n = 192). Participants completed a six alternative forced choice emotion recognition task following consumption of 0.4 g/kg alcohol or placebo. Dependent variables were recognition accuracy (i.e. hits) and false alarms.

RESULTS

There was no clear evidence of differences in recognition accuracy between groups ( ps > .58). In study one, there were more false alarms for anger in the alcohol compared to placebo group ( n = 52 and 56, respectively; t(94.6) = 2.26, p = .024, d = .44) and fewer false alarms for happiness ( t(106) = -2.42, p = .017, d = -.47). However, no clear evidence for these effects was found in study two (alcohol group n = 96, placebo group n = 93, ps > .22). When the data were combined we observed weak evidence of an effect of alcohol on false alarms of anger ( t(295) = 2.25, p = .025, d = .26).

CONCLUSIONS

These studies find weak support for biased anger perception following acute alcohol consumption in social consumers, which could have implications for alcohol-related aggression. Future research should investigate the robustness of this effect, particularly in individuals high in trait aggression.

Inhibiting automatic negative social responses in alcohol intoxication: interactions with theory of mind ability and level of task guidance

RATIONALE

Alcohol intoxication is associated with socially disinhibited behaviours that may reflect impaired social cognitive abilities that guide social behaviour. The effects of alcohol on social cognition and how this may contribute to disinhibited behaviour are poorly understood. The aim of this study was to examine whether intoxicated individuals could inhibit automatic negative responses to negative social information, whether these difficulties were reliant on theory of mind (ToM) ability and whether intoxicated individuals were able to adjust verbal responses when provided with guidelines about how to respond.

METHODS

Sixty-four participants aged between 18 and 34 (balanced for gender) consumed a beverage containing either placebo or alcohol calculated to achieve a target BrAC of 0.080%, before completing a Flanker task, a go/no-go task and a novel measure of social disinhibition, the social disinhibition task.

RESULTS

Results indicate that alcohol-intoxicated individuals can inhibit negative responses to negative social information, but display difficulty inhibiting negative responses to social information that requires ToM. They also suggest that people under the influence of moderate-to-high-dose alcohol can adjust their responses when provided with specific guidelines on how to respond.

CONCLUSIONS

These findings may have important implications for understanding negative alcohol-related behaviours and promote the consideration of social context, social pressure and social cognitive abilities in the development of public policy and targeted interventions to prevent alcohol-related antisocial behaviours.

A moderate dose of alcohol selectively reduces empathic accuracy

RATIONALE

Drinking alcohol is associated with various interpersonal effects, including effects on cognitive empathy. Empathic accuracy (EA) is a form of cognitive empathy concerned with perceivers' accuracy in inferring a target's thoughts and feelings. The effects of alcohol on EA have not previously been studied.

OBJECTIVES

We examined the effect of a moderate alcohol dose on EA in social drinkers.

METHODS

Fifty-four men with varying levels of hazardous drinking according to the Alcohol Use Disorders Identification Test (AUDIT) participated in a randomized, double-blind, between-group study. The alcohol group received 0.56 g/kg alcohol in a vodka and tonic-mixed drink. The placebo group received tonic, with 4 ml of vodka sprayed on top. All participants performed an EA task that involved watching 16 videos of people narrating positive and negative emotional autobiographical events and continuously rating how targets felt while narrating.

RESULTS

There were no significant main effects of beverage condition on the EA task. There was an effect of the condition by AUDIT interaction for EA on the positive videos. Post-hoc simple contrasts revealed that in participants with lower AUDIT scores, the alcohol condition had lower EA for positive videos than the placebo condition. No significant main effect for condition occurred in the participants with higher AUDIT scores.

CONCLUSIONS

The effect of condition in participants with lower AUDIT scores indicates alcohol selectively reduced EA in individuals low on hazardous drinking. This suggests either alcohol-induced impairments of EA for positive events or a positivity bias in men at low risk for alcohol dependency.

Titrating Tipsy Targets: The Neurobiology of Low-Dose Alcohol

Limited attention has been given to our understanding of how the brain responds to low-dose alcohol (ethanol) and what molecular and cellular targets mediate these effects. Even at concentrations lower than 10mM (0.046 g% blood alcohol concentration, BAC), below the legal driving limit in the USA (BAC 0.08 g%), alcohol impacts brain function and behavior. Understanding what molecular and cellular targets mediate the initial effects of alcohol and subsequent neuroplasticity could provide a better understanding of vulnerability or resilience to developing alcohol use disorders. We review here what is known about the neurobiology of low-dose alcohol, provide insights into potential molecular targets, and discuss future directions and challenges in further defining targets of low-dose alcohol at the molecular, cellular, and circuitry levels.

Alcohol acutely enhances decoding of positive emotions and emotional concern for positive stimuli and facilitates the viewing of sexual images

RATIONALE

Social cognition influences social interactions. Alcohol reportedly facilitates social interactions. However, the acute effects of alcohol on social cognition are relatively poorly studied.

METHODS

We investigated the effects of alcoholic or non-alcoholic beer on emotion recognition, empathy, and sexual arousal using the dynamic face emotion recognition task (FERT), Multifaceted Empathy Test (MET), and Sexual Arousal Task (SAT) in a double-blind, random-order, cross-over study in 60 healthy social drinkers. We also assessed subjective effects using visual analog scales (VASs), blood alcohol concentrations, and plasma oxytocin levels.

RESULTS

Alcohol increased VAS ratings of stimulated, happy, talkative, open, and want to be with others. The subjective effects of alcohol were greater in participants with higher trait inhibitedness. Alcohol facilitated the recognition of happy faces on the FERT and enhanced emotional empathy for positive stimuli on the MET, particularly in participants with low trait empathy. Pictures of explicit sexual content were rated as less pleasant than neutral pictures after non-alcoholic beer but not after alcoholic beer. Explicit sexual pictures were rated as more pleasant after alcoholic beer compared with non-alcoholic beer, particularly in women. Alcohol did not alter the levels of circulating oxytocin.

CONCLUSIONS

Alcohol biased emotion recognition toward better decoding of positive emotions and increased emotional concern for positive stimuli. No support was found for a modulatory role of oxytocin. Alcohol also facilitated the viewing of sexual images, consistent with disinhibition, but it did not actually enhance sexual arousal. These effects of alcohol on social cognition likely enhance sociability.

TRIAL REGISTRATION

www.clinicaltrials.gov/ct2/show/NCT02318823.

Drug effects on responses to emotional facial expressions: recent findings

Many psychoactive drugs increase social behavior and enhance social interactions, which may, in turn, increase their attractiveness to users. Although the psychological mechanisms by which drugs affect social behavior are not fully understood, there is some evidence that drugs alter the perception of emotions in others. Drugs can affect the ability to detect, attend to, and respond to emotional facial expressions, which in turn may influence their use in social settings. Either increased reactivity to positive expressions or decreased response to negative expressions may facilitate social interaction. This article reviews evidence that psychoactive drugs alter the processing of emotional facial expressions using subjective, behavioral, and physiological measures. The findings lay the groundwork for better understanding how drugs alter social processing and social behavior more generally.

The effects of alcohol on the recognition of facial expressions and microexpressions of emotion: enhanced recognition of disgust and contempt

OBJECTIVE

The study compared alcohol's effects on the recognition of briefly displayed facial expressions of emotion (so-called microexpressions) with expressions presented for a longer period.

METHOD

Using a repeated-measures design, we tested 18 participants three times (counterbalanced), after (i) a placebo drink, (ii) a low-to-moderate dose of alcohol (0.17 g/kg women; 0.20 g/kg men) and (iii) a moderate-to-high dose of alcohol (0.52 g/kg women; 0.60 g/kg men). On each session, participants were presented with stimuli representing six emotions (happiness, sadness, anger, fear, disgust and contempt) overlaid on a generic avatar in a six-alternative forced-choice paradigm. A neutral expression (1 s) preceded and followed a target expression presented for 200 ms (microexpressions) or 400 ms. Participants mouse clicked the correct answer.

RESULTS

The recognition of disgust was significantly better after the high dose of alcohol than after the low dose or placebo drinks at both durations of stimulus presentation. A similar profile of effects was found for the recognition of contempt. There were no effects on response latencies.

CONCLUSION

Alcohol can increase sensitivity to expressions of disgust and contempt. Such effects are not dependent on stimulus duration up to 400 ms and may reflect contextual modulation of alcohol's effects on emotion recognition.

Similar effects of intranasal oxytocin administration and acute alcohol consumption on socio-cognitions, emotions and behaviour: Implications for the mechanisms of action

Oxytocin (OT) plays a critical role in the formation of long lasting social attachments across a range of mammalian species. Raising intracerebral OT levels by intranasal administration of the neuropeptide (inOT) can also have pronounced effects on human sociocognitive functioning. inOT has been associated with increasing altruism, generosity, empathy and trust while decreasing fear, anxiety and stress reactions via neural mechanisms which are yet to be fully elucidated. The observation of the prosocial effects of OT has led to speculation about the role the peptide might play in some psychiatric conditions and debate as to its potential therapeutic uses. Here we note the great similarity in the sociocognitive effects that can be induced by inOT and the effects of acute consumption of modest does of alcohol. We further reflect on how both compounds may act on limbic and prefrontal cortical structures to increase GABAergic transmission, thereby facilitating the release of prepotent responses, that is, more automatic responses which are associated with earlier developmental stages.

A specific association between facial disgust recognition and estradiol levels in naturally cycling women

Subtle changes in social cognition are associated with naturalistic fluctuations in estrogens and progesterone over the course of the menstrual cycle. Using a dynamic emotion recognition task we aimed to provide a comprehensive description of the association between ovarian hormone levels and emotion recognition performance using a variety of performance metrics. Naturally cycling, psychiatrically healthy women attended a single experimental session during a follicular (days 7–13; n = 16), early luteal (days 15–19; n = 14) or late luteal phase (days 22–27; n = 14) of their menstrual cycle. Correct responses and reaction times to dynamic facial expressions were recorded and a two-high threshold analysis was used to assess discrimination and response bias. Salivary progesterone and estradiol were assayed and subjective measures of premenstrual symptoms, anxiety and positive and negative affect assessed. There was no interaction between cycle phase (follicular, early luteal, late luteal) and facial expression (sad, happy, fearful, angry, neutral and disgusted) on any of the recognition performance metrics. However, across the sample as a whole, progesterone levels were positively correlated with reaction times to a variety of facial expressions (anger, happiness, sadness and neutral expressions). In contrast, estradiol levels were specifically correlated with disgust processing on three performance indices (correct responses, response bias and discrimination). Premenstrual symptoms, anxiety and positive and negative affect were not associated with emotion recognition indices or hormone levels. The study highlights the role of naturalistic variations in ovarian hormone levels in modulating emotion recognition. In particular, progesterone seems to have a general slowing effect on facial expression processing. Our findings also provide the first behavioural evidence of a specific role for estrogens in the processing of disgust in humans.

Differential effects of MDMA and methylphenidate on social cognition

Social cognition is important in everyday-life social interactions. The social cognitive effects of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') and methylphenidate (both used for neuroenhancement and as party drugs) are largely unknown. We investigated the acute effects of MDMA (75 mg), methylphenidate (40 mg) and placebo using the Facial Emotion Recognition Task, Multifaceted Empathy Test, Movie for the Assessment of Social Cognition, Social Value Orientation Test and the Moral Judgment Task in a cross-over study in 30 healthy subjects. Additionally, subjective, autonomic, pharmacokinetic, endocrine and adverse drug effects were measured. MDMA enhanced emotional empathy for positive emotionally charged situations in the MET and tended to reduce the recognition of sad faces in the Facial Emotion Recognition Task. MDMA had no effects on cognitive empathy in the Multifaceted Empathy Test or social cognitive inferences in the Movie for the Assessment of Social Cognition. MDMA produced subjective 'empathogenic' effects, such as drug liking, closeness to others, openness and trust. In contrast, methylphenidate lacked such subjective effects and did not alter emotional processing, empathy or mental perspective-taking. MDMA but not methylphenidate increased the plasma levels of oxytocin and prolactin. None of the drugs influenced moral judgment. Effects on emotion recognition and emotional empathy were evident at a low dose of MDMA and likely contribute to the popularity of the drug.

Effects of acute alcohol consumption and processing of emotion in faces: Implications for understanding alcohol-related aggression

The negative consequences of chronic alcohol abuse are well known, but heavy episodic consumption ("binge drinking") is also associated with significant personal and societal harms. Aggressive tendencies are increased after alcohol but the mechanisms underlying these changes are not fully understood. While effects on behavioural control are likely to be important, other effects may be involved given the widespread action of alcohol. Altered processing of social signals is associated with changes in social behaviours, including aggression, but until recently there has been little research investigating the effects of acute alcohol consumption on these outcomes. Recent work investigating the effects of acute alcohol on emotional face processing has suggested reduced sensitivity to submissive signals (sad faces) and increased perceptual bias towards provocative signals (angry faces) after alcohol consumption, which may play a role in alcohol-related aggression. Here we discuss a putative mechanism that may explain how alcohol consumption influences emotional processing and subsequent aggressive responding, via disruption of orbitofrontal cortex (OFC)-amygdala connectivity. While the importance of emotional processing on social behaviours is well established, research into acute alcohol consumption and emotional processing is still in its infancy. Further research is needed and we outline a research agenda to address gaps in the literature.